1. Field of the Invention
The present invention relates to a tubular body such as a golf club shaft.
2. Description of the Related Art
A tubular body has various applications. Since the tubular body has a cavity formed therein, the tubular body is lightweight and has high rigidity. The tubular body which is lighter in weight and has excellent rigidity and strength can be useful for various applications.
An example of the applications for the tubular body is a golf club shaft. A golf club shaft using a carbon fiber is available. This type of shaft is also referred to as a carbon shaft. A carbon shaft which is lightweight and has high strength can be manufactured by using the carbon fiber.
The lightweight shaft contributes to enhancement in head speed. In respect of the head speed, a shaft which is lighter in weight is preferable. The lightweight tubular body is effective in many fields.
On the other hand, weight reduction causes reduction in strength. In addition, the weight reduction is apt to cause excessive reduction in rigidity of a shaft. In many fields, the tubular shaft which is lightweight and has high strength is worth.
Japanese Patent Application Laid-Open No. 9-117968 discloses a golf club shaft having a hollow part having a rib-like reinforcing part. This structure maybe useful for a shaft which is lightweight while maintaining strength and rigidity.